This really isn’t true for our family. We have had some wonderful holidays from 6m to 3-4yrs. Can’t think of a bad one! We’ve done city breaks, beach holidays, villas in the middle of nowhere, loads!
We don’t really stick to a routine, we eat out when we want to, sleep when we want to, don’t have to juggle work/nursery/etc. Usually we pick a fun activity, have a long leisurely lunch out, chill in the park or on the beach, see a museum, exhibition etc. Then pop to a deli or market for a relaxing dinner and glass of wine when the children are asleep.
I absolutely love holidays with little ones, they haven’t impacted us that much and not a huge amount of difference than holidays before (well no bar hopping until 3am, but I’m not that bothered about that now!).
I recommend Barcelona, Berlin, Amsterdam, Rome, Sardinia. I find toddlers a lot less stroppy in holiday as everything is fun (plus ice cream!). Much easier to deal with the usual niggles when you’re not working the next day, eating lovely food, and the sun on your back! Beaches with good bars are great. Full toilet facilities and you can have a sundowner whilst the children play in the sand!